1. Field of the Invention
The present invention relates to a numerical control device having function of monitoring operation condition and automatically restarting a CPU for HMI when HMI operation abnormality occurs.
2. Description of the Related Art
In a numerical control device for controlling a machining tool or an industrial machine, a circuit or a personal computer for HMI is often added when high-performance HMI function for graphic representation is necessary. The numerical control device with HMI function, in general, can not update the screen and the screen freezes or no screen is displayed when a universal operating system stops by malfunction of the application software for HMI function or a storage device.
FIG. 7 is a schematic diagram showing a numerical control device with the HMI function in a conventional art. A numerical control device 100 includes a CPU 10 for numerical control which controls a machining tool and a HMI function unit 20 which performs high-performing graphic representation, and performs data exchange using interface region 50. A CPU 40 for HMI is installed in the HMI function unit 20. The HMI function unit 20 is connected to a display unit 30 and executes a universal operating system using the CPU 40 for HMI.
The CPU 10 for numerical control and the HMI function unit 20 exchange data with each other via the interface region 50, in the numerical control device with the HMI function described above. It has been impossible for the CPU for numerical control 10 to identify a display abnormality in the HMI function unit 20. For this reason, no information is given to the operator in maintenance work after the abnormality occurs, and it takes a long time before the cause is investigated. In addition to that, no machine information is seen on the display in the abnormality occurrence, there is also a safety problem.
As a conventional technique to cope with the abnormality which occurs in HMI function, such a technique is disclosed that having two kinds of operation systems (Hereinafter referred to as “OS”) in that, when one OS does not work on boot, another OS for maintenance is configured to work (See, for example, Japanese Patent Laid-Open No. 2012-018454).
However, the conventional technique, described in Japanese Patent Laid-Open No. 2012-018454, can operate the maintenance OS when an abnormality occurs on boot, but does not consider the case where an abnormality occurs during normal operation.